Animal dehorning apparatus

ABSTRACT

A shear-type dehorning apparatus comprising a pair of generally parallel guide brackets or rails, a fixed blade attached at one end and a shearing blade guided between the pair of guide rails and connected to a piston within a cylinder. A hand operated valve is an integral part of a handle on the cylinder housing and controls introduction of compressed gas from a storage container to thereby provide a power actuated dehorner requiring neither electricity nor an auxiliary engine for operation.

United States Patent Nicholson [451 July 18, 1972 [54] ANIMAL DEHORNING APPARATUS [72] Inventor: Donald R. Nicholson, Route 1, Box 102,

Colby, Kans. 67701 [22] Filed: Nov. 7,1969

[21] Appl.No.: 874,813

[52] U.S. ........30/228 [51] Int. ..B26b 15/00 [58] Field of Search ..30/180, 228, 241, 242, 443, 30/245, 258

l 56] References Cited UNITED STATES PATENTS 215,312 5/l879 Babbitt ..30/243 1,091,607 3/1914 3,177,584 4/1965 Cockerill ..30/228 3,255,525 6/1966 FrenzeL. ..........30/22B X 2,941,430 6/1960 Klingler ...81/301 X 3,030,838 4/1962 Klinger ..81/301 X Primary Examiner-Theron E. Condon Assistant Examiner-J. C. Peters Attorney-Burns, Doane, Swecker & Mathis ABSTRACT A shear-type dehorning apparatus comprising a pair of generally parallel guide brackets or rails, a fixed blade attached at one end and a shearing blade guided between the pair of guide rails and connected to a piston within a cylinder. A hand operated valve is an integral part of a handle on the cylinder housing and controls introduction of compressed gas from a storage container to thereby provide a power actuated dehomer requiring neither electricity nor an auxiliary engine for operation.

11 Claims, 8 Drawing Figures Patented July 18, 1972 4 Sheets-Sheet l INVESTOR DONALD R. NICHOLSON M A b Ewan; Qua div: 5 p; Swim .nmmn's Patented July 18, 1972 3,676,929

4 Sheets-Sheet 2 M nllllll llllllllpllln IN VENTOR DONALD R. NICHOLSON BY gov/u", beam-(Bound, Mama 6 Mat/u: ATTORNEYS Patented July 18, 1972 4 ets-Sheet 3 6. "1g 1 m -l a v K 89% fil a h 59 FIG 4 5% Q I \r 87 g 28 1 i i 1 SE/TT l V \i INVENTOR DONALD R. NICHOLSON BY u/ns boa/u mdxct aver/(0: a! ums ATTORNEYS Patented July 18, 1972 4 Sheets-Sheet 4 IN VENTOR DONALD R. NICHOLSON ATTORNEYS BY gum/w, Boa/n2 :Ewuaw, Ewes cm a! Ham:

ANIMAL nsnomvmo APPARATUS This invention relates to dehorning apparatus suitable for severing the horns from animals, such for example, as cattle in a rapid and advantageous manner.

Horns of cattle generally comprise two parts, an outer horny shell and an inner bone structure. The horny portion develops first, emerging from a germinal tissue layer at the base of the skull. The bone structure then follows this horny shell. A cornual artery extends along the lateral surface of the cows head, beneath the germinal tissue and into the bone structure of the horn.

In dehorning an animal, it is necessary to remove the abovementioned germinal tissue in order to prevent regrowth of the animals horn. Further, it is desirable to expose the cornual artery before it enters into the bone structure of the horn. If the horn is severed too far away from the animal's head, the artery will be in the bony stump that remains, thereby making it difficult to stop excessive bleeding.

Several shear types of dehorning apparatus have been utilized in the past. At least one known type comprises a fixed and movable blade within a guide frame wherein the movable blade may be driven by a blow from a mallet. Other shear-type dehorning devices have utilized long leverage handles, gas pressure delivered from an explosive cartridge, hydraulic pressure delivered from a fluid sump, and an electrically driven reciprocating shaft to provide the driving of movable blade.

These previously known dehorning devices all have certain disadvantages. For example, dehorning apparatus utilizing a mallet as a motive power is difficult to accurately position and manipulate, often lacks sufficient power to sever the horn of a full-grown animal and requires two persons for the dehorning operation one to hold, and one to hit. Dehomers utilizing an explosive cartridge are objectionable in that the noise tends to frighten and excite not only the animal being dehorned, but other animals that are in the same vicinity. In addition to being relatively slow in actuation, hydraulic systems have required relatively complicated and intricate power sources with separate oil lines containing hydraulic fluid between the power cylinder and the prime mover, such as an internal combustion engine, and are heavy and unwieldy to manipulate. Electrically driven systems relying on power from an electric motor can be used only where electricity is available. Also, shock hazards are not insignificant in situations where a number of animals are being dehorned and the cutting blades are placed in a disinfectant solution between successive dehorning operations.

It is therefore a primary object of the invention to provide a novel animal dehorning apparatus which obviates the foregoing problems and disadvantages of the prior dehorning devices in that it is of lightweight construction, easily operable by one person, is substantially silent in operation, and requires neither a gasoline engine nor electricity when in use.

It is another object of the invention to provide a novel dehorning apparatus having minimal structure forward of the fixed blade so that the device may be placed close to the head of the animal to sever the horn below the animal's hairline and germinal tissue layer, and also to be directly usable on a variety of horn sizes.

It is a further object of the invention to provide a novel dehorning device that will automatically reset itself once actuated, and will not jam when the animals hair is severed next to the base of the horn, so that the operator may be free to perform other essential steps of the dehorning operation.

It is another object of the invention to provide a novel animal dehorning apparatus which is portable for easy use in remote areas and operable from a cylinder of compressed fluid such as air or carbon dioxide.

It is yet another object of the invention to provide an animal dehorning apparatus having blades which will not jam, will readily accommodate various sizes of horns, and crimp any arteries leading into the animal's horn to prevent hemorrhaging therefrom.

It is still another object of the invention to provide a novel dehorning device which is extremely rapid in actuation to minimize the time spent for dehorning an animal, and rugged in operation and design to have a long life with a minimum of maintenance required.

Further objects and advantages of the invention will become more fully apparent from the claims and from the following detailed description taken in conjunction with the accompanying drawings.

THE DRAWINGS FIG. I is a schematic view showing an animal to be dehorned and dehorning apparatus embodying the present invention in a ready position;

FIG. 2 is a side elevation of the dehorning apparatus in partial section to show the internal cylinder structure of the apparatus of FIG. I;

FIG. 3 is an end elevation in section taken along section line 3-3 of FIG. 2:

FIG. 4 is an enlarged view of only the power cylinder of FIG. 2 showing the piston located in its normal position;

FIG. 5 is a view similar to FIG. 4, showing only a lower portion of one cylinder with the piston head in an actuated position which would exist immediately after the animal's horn is severed and a partial actuation of the damping cylinder which absorbs the momentum of the connecting shaft and cutting blade;

FIG. 6 (on sheet 1) is a cross-sectional view taken along line 6-6 of FIG. 4, showing the apertures in the internal damping cylinder head;

FIG. 7 is a view in section taken along section line 7-7 of FIG. 3, showing the trigger valve mechanism; and

FIG. 8 is a plan view in section taken along section line 8-8 of FIG. 7.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIG. I, there is shown an animal I0 having horny protrusions 11 extending from the top of its skull. Extending within the interior of the horny structure are cornual arteries 12. Surrounding the base of the horny structure is a layer of germinal tissue 13 and a hair ring 14.

The animal dehorning device 20 of the present invention is shown positioned around the horn II in a posture generally sloping downwardly along the animal's head in a position ready for actuation. A stationary blade 22 is attached between two parallel guide rails 24 and is laid against the animal's skull, between the base of the horn 11 and the animal's ear 15. A translatable shearing blade 26 is mounted for reciprocation within the guide rails 24 and is driven by a power cylinder 28. A suitable source of pressurized fluid, such as for example carbon dioxide gas, may be supplied by a conventional pressurized cylinder 30 and connected to the power cylinder 28 by a flexible hose or conduit 32. Tank pressures on the order of -150 pounds, which are readily available, are suitable. The conduit 32 may be attached to the base of a first handle 34 having a hollow channel therein which leads to a trigger operated valve mechanism 36. The valve in the actuated position leads into a passage through the power cylinder end cap 38 to supply pressurized fluid within the cylinder which serves to actuate the shearing blade 26.

To aid in manipulating the instrument around the head of the animal and over its horn, a second handle 40 is connected to the power cylinder 28in a posture approximately ISOfrom that of the first handle 34. With the dehorning apparatus positioned as shown in FIG. I, it will be readily appreciated that a single operator may easily manipulate the apparatus by grasping the second handle 40 and first handle 34, placing the apparatus over an animal's horn, as shown in FIG. I, and momentarily actuating the trigger valve mechanism with an index finger to thereby etfect the shearing of the horn.

Referring now to FIGS. 2 and 3, the dehorning device 20 is shown provided with a pair of guide rails 24 which serve to guide, in reciprocating motion, a shearing blade 26. The shearing blade is provided with a generally V-shaped cutting edge 42.

Attached to the extremities of the guide rails 24 is a fixed or stationary blade 22 which may be secured as by machine screws 44 or other suitable fasteners. The stationary blade 21 is provided with a generally arcuate shaped leading or cutting edge 46. As best seen in FIG. 2, the edge 46 is provided with an offset lip 48. Therefore, as the shearing blade 26 descends down the guide rails and past the fixed blade, hair and skin from the animal may be displaced into a void, as at 49, below the offset lip 48 and thus prevent jamming of the cutting blades. Further, the trailing edge of the stationary blade 22 is provided with a generally square abutment 51. This abutment serves the dual purpose of limiting movement of the fixed blade into the horn of the animal and picks up severed arteries and tissue and crimps them against the horn so as to prevent hemorrhaging.

The movable shearing blade 26 is connected to a drive shaft 50 as by means of a bifurcated adapter 52. The shaft is threaded into the upper end of the adapter, as best seen in FIG. 2, and the legs 54 encompass an upper portion of the shearing blade 26. A suitable fastener 56, or a plurality of fasteners, may then be inserted normally through the legs and blade to lock the two together.

The drive shaft 50 extends through the bottom wall 58 of the gas cylinder 28 and abuts against the base of the top one 60 of a pair of piston head forming discs 60 and 61.

A diaphragm member 63 is positioned between the circular piston head discs and is provided with an upturned peripheral lip 65. The diaphragm 63 may be constructed of leather or other pliable materials and serves to maintain contact with the inner cylinder surface 67.

The top piston head disc 60 is provided with a chamfered edge 69 to permit gas under pressure to enter between the edge 69 of the top cylinder disc and the inner circumference of the lip 65 to press the lip against the inner cylinder wall 67 in sealing contact. The piston head discs and diaphragm are joined together, as by a plurality of machine bolts 71 or other suitable fasteners.

Referring now to FIGS. 4 and 5, the piston head 59 is normally held in a posture remote from the cylinder base wall 58 by a helical cone spring 73. The force required to displace the spring 73 as the cylinder head moves downward is a function of the so-called spring constant and the displacement distance. The spring constant in spring 73 is relatively small for initial displacements of the spring, but increases as the spring is fully compressed, as best seen in FIG. 5. Therefore, it will be appreciated that as the piston head descends, the force required to displace the spring is actually increasing, with the maximum occurring as the spring is completely compressed. The dehorning apparatus has been designed to take advantage of this variable force to counter momentum of the piston head and cutting blade to prevent shock loading of the parts, as will be more fully described hereinafter.

The periphery of the bottom piston head disc 61 is provided with an annular notch or facing 75 which will abut against a peripheral extending ledge 77 protruding within the interior of the power cylinder 28. At the bottom of the cutting stroke, these surfaces will abut and simultaneously the end wall 83 of a cup 79 in the bottom cylinder head disc 61 will contact the bottom cylinder wall 58. Thus, further downward movement of the piston head is prevented. It will be readily appreciated that the momentum force of this abutting contact represents a potential area of wear and possible failure. The above discussed coil spring 73, however, has been designed to provide increasingly greater counter force as the piston approaches the end wall to tend to reduce the impact and noise.

Further in this connection, the bottom one of the cylinder head discs 61 is desirably provided with a cylindrical damping cup 79. The cup is adapted to receive through an aperture 81 in an end wall 83 thereof the upper end of the drive shaft 50. The drive shaft 50 is provided at its upper extremity with an enlarged head portion 85. The interior of the damping cup is filled with a viscous fluid which is prevented from leaking between the drive shaft and the end wall aperture 81, as by means ofa pair of O ring seals 87.

A helical compression spring 89, which may be square in cross section, surrounds the upper end of the drive shah 50 and is positioned between the lower edge of the head portion 85 and a circular disc or washer 91 inset into the end wall 83 of the damping cup.

Referring now to FIG. 6 (on sheet I), a plurality of generally cone-shaped flow passages 93 are provided through the enlarged head 85 of the drive shaft 50. These passages permit fluid to traverse from one side of the head portion 85 to the other in a metered fashion, thus combining with compression spring 89 to provide a damping force which cushions the abrupt stop of downward travel of the drive shaft 50 and movable cutting blade 26 when piston head surface 75 engages surface 77 of the cylinder.

Referring now to FIGS. 7 and 8, there is shown a detail of a suitable three-way valve mechanism and trigger actuation means. An upper power cylinder cap 95 is fastened, as by a plurality of fasteners 97, to the power cylinder 28. An O-ring 99 is positioned at the inner face of these two members to provide a fluid seal at this junction.

Cap 95 is provided with an integral handle 34 having a fluid passage I01 therein which leads from the hose 32 (see FIG. I) to a trigger-operated, three-way valve mechanism 36. The valve has a first cylindrical casing which may be threaded into a stern extension 106 of handle 34. The casing 105 is provided at one end with a circular resilient seat 109 which abuts against the periphery of a passage 107, transverse to the fluid passage l0I. A valve head 11] seats against the resilient member 109 and is normally held in a closed position by a compression spring 103 to prevent fluid from traversing passage 107. The valve head 111 is connected to a stem 113 which in turn is connected to a cylindrical body member 115 slidingly mounted within a cylindrical wall of the casing 105. An O-ring 119 is positioned to extend into engagement with the walls of the cylindrical body member I15.

The stem 106 is fashioned with a fluid passage 12] which provides fluid communication between the interior of the power cylinder 28 and the casing I05 along the line of the double arrow shown in FIG. 7. A plurality of apertures 123 are fashioned through the casing 105 directly behind the resilient seat member and connect the passage 121 and the cylindrical void I17 in the casing I05. A hollow cylindrical sleeve member 125 extends coaxially within the cylindrical body 115 and is provided with a generally U-shaped extension 127 which provides fluid communication between the passage I21 through the cylindrical body 115 and the coaxial sleeve 125 to the portion of the cylindrical body 115 remote from the valve head I 11.

A second valve head 129 is connected to the U-shaped extension 127 and is provided at its inner periphery with a circular, resilient sealing washer 131 which abuts against the outer periphery 133 of the cylindrical body 115 when the trigger I35 is pulled to a ready position before the dehorner is actuated. In this abutting posture (see FIG. 7), the fluid passage that is maintained through channel 121 to the outer interior of the cylindrical body 115, as previously discussed, is sealingly closed. A finger actuated trigger member 135, which may be journaled for pivotal movement around an axis 137, is shaped to hold the second valve head 129 in a sealing posture when the trigger is pulled toward the handle 34.

When the trigger member 135 is released, pressure behind valve head 129 will force it into an open posture, as shown in phantom in FIG. 7, thus permitting a controlled bleed passage to the atmosphere. This controlled bleed will prevent an uncontrolled rapid return of the piston head and thus prevent damaging abutment of the cylinder head 59 with the cap 95.

OPERATION When it is desired to dehorn an animal, the animal is normally run into a squeeze chute or otherwise rendered essentially immobile, and the dehorning device is positioned over the horn of the animal, generally as shown in HO. 1. In this connection, the fixed blade is then positioned against the animal's head to sever the germinal tissue and crimp the cornual artery against the base of the horns bone structure. One person may hold the dehorning apparatus in the correct position by the handles 34 and 50, and actuate the shearing blade by merely pulling trigger 135 with an index finger.

Referring now to FIGS. 7 and 8, it will be seen that such a motion will force the second valve head 129 against the cylinder body 115, closing the bleed passage to the atmosphere and simultaneously unseating the valve head ill from the resilient seat 109. The pressurized fluid within passage 10] then bypasses the valve head I11 and exist from the cylindrical void 117 in the casing 105, through the plurality of apertures I23 into the passage 121 leading into the power cylinder.

The ower piston head 59 starts to descend as a result of pressure accumulated between the cylinder head and the end cap 95. Resisting this motion, in addition to friction, is the counterforce created by the conical compression spring 73. The spring resistance to movement, however, is variable, as previously discussed, being at a minimum during the initial deflection stages and increasing as the spring is compressed.

As more fluid is rapidly liberated into the power cylinder, the piston head 59 continues rapidly to descend, forcing drive shaft 50, which is abutted against the bottom of the top disc 60, downward thus advancing shearing blade 26 toward the fixed blade 22. The gap existing between the forward arcuate edge of the fixed plate 46 and the V-shaped shearing edge 42 closes around the horn of the animal. As the piston head reaches the lower extremities of the power cylinder, the animal's horn will be simultaneously centered within the arcuate blade and severed by the V-shaped blade passing the cutting edge 46 thereof.

As an animals horn is severed, the blade 26, coupling 52, and drive shaft 50, combined with the cylinder head 59, have gained considerable momentum in the course of their rapid movement. The momentum of the piston head 59 and its associated parts, however, is thereafter being absorbed at an increasingly greater rate by the greater force required to displace the conical spring as it nears full compression. When the rim 75 of the piston head 59 abuts surface 77, the bottom portion of the power cylinder 28 as discussed supra, causes the cylinder to halt abruptly. However, the piston head 59, being of a lightweight magnesium or aluminum alloy, does not create a heavy impact, and the remainder of the removable cutting blade assembly, including drive shah S0, is free to cont1n ue moving.

To assist in arresting the momentum of the movable blade 26 and its assembly, including the blade adapter 52 and the drive shaft 50, the head 85 of the drive shaft 50 is not fixedly coupled to the piston head 59. Thus, the movable blade assembly is free to continue downward movement against the compression coil spring 89 and against the resistance of the damping fluid flowing through the tapered orifices 93. Therefore, the momentum of the movable blade assembly is arrested or damped separately from piston head 59. This reduces the force of impact when piston head 59 strikes the base portions of the cylinder casing. This feature allows the over-all weight of the dehorning apparatus to be reduced since wall thicknesses of the cylinder 28 and the piston head 59 may be made smaller than would otherwise be possible, thus allowing for the weight of the apparatus to be easily manageable by a single person.

Once the downward shearing stroke is completed and the finger actuated trigger 135 is released, several actions take place. The compressed helical spring 89 (see FIG. 5) in the damping cup expands to urge shaft 50 and the movable cutting blade 26 toward piston head 59 to its normal position, as illustrated in FIG. 4. Piston head 59 is urged in the same direction away from the fixed blade 22 by the compressed helical spring 73. The combined action of these springs 89 and 73 has been found sufficient to prevent the cutting blades from being held together by hair or skin, which is a problem with many dehorners, and thus facilitates prompt separation of the blades.

Further, the helical spring I03 (see FIGS. 7 and 8) associated with the released trigger 135 will force the valve head 111 closed, thus starting the trigger in a downward movement. Fluid pressure within the power cylinder then will travel through passage 12! into the cylindrical void 117 of the casing 105. Since the valve 111 is maintained in a closed position by the helical spring [03, the fluid within the cylinder will circulate through the coaxial sleeves H5 and 125 behind the second valve head 129 which will be forced open to the atmosphere. A flow path thus established to the atmosphere will permit the accumulation of fluid within the power cylinder 28 to bleed away as the compression spring 73 returns the cylinder head to the cap 95. The return spring 89 will similarly reposition the drive shaft 50 and the head against the upper one 60 of the two cylinder head disc. The mechanism is thus automatically repositioned for subsequent cutting strokes.

From the foregoing, it is evident that the present invention provides a dehorning apparatus which is light in weight and easily transportable in the field and which may be operated from a power source which is also easily transportable, utilizing a single flexible hose conduit. The cutting mechanism, operating from a gas cylinder, is rapid in operation thus preventing hazards to the animal if the animal should inadvertently move its head during the cutting operation.

The arcuate shape of the fixed blade has a centering effect as the V-shaped shearing blade contacts the animals horn. Further, this blade combination permits the device to be utilized on animals of various horn sizes, yet crimps the cornual artery and tissue against the exterior of the horn to prevent hemorrhaging. A minimum amount of material forward of the arcuate shaped fixed blade permits the operator to position the dehorning device very close to the animal's head between the horn and ear thus enabling the mechanism to easily sever the germinal tissue. The offset 49 at the fixed blade allows tissue and hair to be diverted into the void formed behind the offset, thus eliminating jamming which has previously been a problem with dehorning devices.

It will be readily realized that the dehorning apparatus described is suitable for operation in remote areas and requires no consumable commodity other than compressed gas, which can be transported in readily available containers. The dehorning apparatus is relatively quiet in operation so as not to disturb nearby animals, and is composed of a relatively few number of parts as compared with previously known power dehorning devices. The momentum arresting and dampening elements in the interior of the power cylinder prevent excessive impact of the cylinder head against the cylinder bottom wall.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment, therefore, is to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims, rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by Letters Patent l. Animal dehorning apparatus comprising a pair of blades mounted for reciprocal movement, and means for moving one of said blades relative to the other comprising a piston slidably mounted in a cylinder, a drive shaft connected at one end to said one blade and coupled at its other end to said piston by means including a head portion adapted to abut against a surface of the piston during the cutting stroke and to move away from said surface upon abrupt stopping of the piston due to collision with a fixed portion of said cylinder, a manually operated valve, and means including a supply of compressed gas connected through said valve to actuate said blade movement.

2. Animal dehorning apparatus as defined in claim 1 further comprising a compression Spring located between the cylinder and the piston for absorbing energy due to the momentum of the piston as it moves to a position where it abuts with said fixed portion of the cylinder and for returning the piston away from said cylinder fixed portion.

3. Animal dehorning apparatus as defined in claim 1 further comprising a damping fluid reservoir mounted on said piston and wherein said other end of the drive shaft includes an enlarged head portion having one surface adapted to abut said piston, said enlarged head portion moving through said fluid afier said abrupt stopping of the piston.

4. Animal dehorning apparatus as defined in claim 3 further comprising a compression spring mounted between one wall of the fluid reservoir and said drive shaft head portion for returning said head portion back to its position abutting said piston.

5. Animal dehorning apparatus as defined in claim 1 wherein said last-mentioned means comprises:

a three-way valve connecting said gas cylinder alternatively to a source of gas under pressure and to the atmosphere, said valve being normally biased closed between said source of gas under pressure and said gas cylinder and being normally biased open between said gas cylinder and the atmosphere.

6. Animal dehorning apparatus as defined in claim 1 wherein said fixed blade contains an offset cutting lip thus forming a cavity for receiving displaced hair and skin behind said lip as said movable blade passes said fixed blade.

7. Animal dehorning apparatus comprising:

a gas cylinder having an end wall at one end and a cap at the other end;

a pair of guide rails extending from said end wall of said cylinder;

a fixed cutting blade secured to said guide rails at a location remote from said cylinder end wall and having a cutting edge generally facing said end wall;

a piston mounted for reciprocation within said cylinder;

a drive shaft connected to said piston head and extending exteriorly of said cylinder end wall toward said fixed blade; movable blade connected to said shaft and mounted to slide along said guide rails toward and away from said fixed blade;

a momentum dampening means for absorbing the energy of said movable blade and drive shaft after the movable blade has cut through the thickest part of the animal horn and the piston abuts against the rigid portion of said cylinder, said dampening means including a fluid dashpot formed by a cup containing a viscous fluid mounted to said piston and a head movable in said cup through said fluid, said last-mentioned head being on the end of said drive shaft connected to said piston; and

means for selectively supplying compressed gas from a remote source of gas under pressure to said gas cylinder to produce movement of said movable blade toward said fixed blade and cause severance of the animal's horn, and for venting said gas cylinder to the atmosphere to thereby allow said movable blade to move away from said fixed blade following severance.

8. Animal dehorning apparatus as defined in claim 7 wherein said drive shaft head is provided with:

a plurality of conical orifices positioned around the periphery of the head to meter fluid therethrough to facilitate a dashpot dampening action.

9. Animal dehorning apparatus as defined in claim 7 comprising:

a further spring member positioned within said dashpot for complementing and adding to the fluid dampening action of said dashpot after the piston has contacted said cylinder end wall and for providing a supplemental force to aid in overcoming resistance to the opening of the blades after removal of the horn.

10. An animal dehorning apparatus comprising:

a frame;

a horn shearing means mounted to said frame for shearing off the horn of an animal. said shearing means comprising a fixed blade and a translating blade, wherein the cutting edge of said fixed blade is concavely curvilinear and the shearing edge of said translating blade is V-shaped, and wherein the surface of said fixed blade has an undercut portion on the side of said fixed blade facing said shearing blade whereby animal hair or germinal tissue severed during the dehorning operation will not excessively jam between the fixed and translating blades;

a cylinder mounted to said frame;

a piston mounted for slidable movement into said cylinder and connected to operate said horn shearing means;

a power source comprising a vessel containing gas under compression and a delivery means connected between said vessel and said cylinder; and

a valve in said gas delivery means for selectively applying gas under pressure to cause actuation of said horn shearing means.

11. Animal dehorning apparatus comprising:

a gas cylinder having an end wall at one end, a cap at the other end, and an annular abutment surface on an inner cylindrical wall;

a pair of guide rails extending from said end wall of said cylinder;

a fixed cutting blade secured to said guide rails at a location remote from said cylinder end wall and having a cutting edge generally facing said end wall;

a piston head mounted for reciprocation within said cylinder and having an outer peripheral portion adapted to engage the annular abutment surface of said cylinder;

a shaft having a head portion adapted to abut against a central portion of said piston head during the cutting stroke and a stem portion extending exteriorly of said cylinder end wall toward said fixed biade;

a movable blade connected to said shaft and mounted to slide along said guide rails toward and away from said fixed blade;

spring means surrounding the stem portion of the shaft that is inside said cylinder when the fixed and movable blades are separated and compressed between said cylinder end wall and piston head for biasing said piston head away from said cylinder end wall, said spring being capable of being compressed into the space between the cylinder end wall and the annular surface when the piston engages the annular abutment surface;

a momentum dampening means for absorbing the energy of said movable blade and drive shaft after the movable blade has cut through the thickest part of the horn and the piston head makes contact with said annular abutment surface; and

means for selectively supplying compressed gas from a remote source of gas under pressure to said gas cylinder to produce movement of said movable blade toward said fixed blade and cause severance of the animal's horn, and for venting said gas cylinder to the atmosphere to thereby allow said movable blade to move away from said fixed blade following severance under the action of said spring means.

I I I i l 

1. Animal dehorning apparatus comprising a pair of blades mounted for reciprocal movement, and means for moving one of said blades relative to the other comprising a piston slidably mounted in a cylinder, a drive shaft connected at one end to said one blade and coupled at its other end to said piston by means including a head portion adapted to abut against a surface of the piston during the cutting stroke and to move away from said surface upon abrupt stopping of the piston due to collision with a fixed portion of said cylinder, a manually operated valve, and means including a supply of compressed gas connected through said valve to actuate said blade movement.
 2. Animal dehorning apparatus as defined in claim 1 further comprising a compression spring located between the cylinder and the piston for absorbing energy due to the momentum of the piston as it moves to a position where it abuts with said fixed portion of the cylinder and for returning the piston away from said cylinder fixed portion.
 3. Animal dehorning apparatus as defined in claim 1 further comprising a damping fluid reservoir mounted on said piston and wherein said other end of the drive shaft includes an enlarged head portion having one surface adapted to abut said piston, said enlarged head portion moving through said fluid after said abrupt stopping of the piston.
 4. Animal dehorning apparatus as defined in claim 3 further comprising a compression spring mounted between one wall of the fluid reservoir and said drive shaft head portion for returning said head portion back to its position abutting said piston.
 5. Animal dehorning apparatus as defined in claim 1 wherein said last-mentioned means comprises: a three-way valve connecting said gas cylinder alternatively to a source of gas under pressure and to the atmosphere, said valve being normally biased closed between said source of gas under pressure and said gas cylinder and being normally biased open between said gas cylinder and the atmosphere.
 6. Animal dehorning apparatus as defined in claim 1 wherein said fixed blade contains an offset cutting lip thus forming a cavity for receiving displaced hair and skin behind said lip as said movable blade passes said fixed blade.
 7. Animal dehorning apparatus comprising: a gas cylinder having an end wall at one end and a cap at the other end; a pair of guide rails extending from said end wall of said cylinder; a fixed cutting blade secured to said guide rails at a location remote from said cylinder end wall and having a cutting edge generally facing said end wall; a piston mounted for reciprocation within said cylinder; a drive shaft connected to said piston head and extending exteriorly of said cylinder end wall toward said fixed blade; a movable blade connected to said shaft and mounted to slide along said guide rails toward and away from said fixed blade; a momentum dampening means for absorbing the energy of said movable blade and drive shaft after the movable blade has cut through the thickest part of the animal horn and the piston abuts against the rigid portion of said cylinder, said dampening means including a fluid dashpot formed by a cup containing a viscous fluid mounted to said piston and a head movable in said cup through said fluid, said last-mentioned head being on the end of said drive shaft connected to said piston; and means for selectively supplying compressed gas from a remote source of gas under pressure to said gas cylinder to produce movement of said movable blade toward said fixed blade and cause severance of the animal''s horn, and for venting said gas cylinder to the atmosphere to thereby allow said movable blade to move away from said fixed blade following severance.
 8. Animal dehorning apparatus as defined in claim 7 wherein said drive shaft head is provided with: a plurality of conical orifices positioned around the periphery of the head to meter fluid therethrough to facilitate a dashpot dampening action.
 9. Animal dehorning apparatus as defined in claim 7 comprising: a further spring member positioned within said dashpot for complementing and adding to the fluid dampening action of said dashpot after the piston has contacted said cylinder end wall and for providing a supplemental force to aid in overcoming resistance to the opening of the blades after removal of the horn.
 10. An animal dehorning apparatus comprising: a frame; a horn shearing means mounted to said frame for shearing off the horn of an animal, said shearing means comprising a fixed blade and a translating blade, wherein the cutting edge of said fixed blade is concavely curvilinear and the shearing edge of said translating blade is V-shaped, and wherein the surface of said fixed blade has an undercut portion on the side of said fixed blade facing said shearing blade whereby animal hair or germinal tissue severed during the dehorning operation will not excessively jam between the fixed and translating blades; a cylinder mounted to said frame; a piston mounted for slidable movement into said cylinder and connected to operate said horn shearing means; a power source comprising a vessel containing gas under compression and a delivery means connected between said vessel and said cylinder; and a valve in said gas delivery means for selectively applying gas under pressure to cause actuation of said horn shearing means.
 11. Animal dehorning apparatus comprising: a gas cylinder having an end wall at one end, a cap at the other end, and an annular abutment surface on an inner cylindrical wall; a pair of guide rails extending from said end wall of said cylinder; a fixed cutting blade secured to said guide rails at a location remote from said cylinder end wall and having a cutting edge generally facing said end wall; a piston head mounted for reciprocation within said cylinder and having an outer peripheral portion adapted to engage the annular abutment surface of said cylinder; a shaft having a head portion adapted to abut against a central portion of said piston head during the cutting stroke and a stem portion extending exteriorly of said cylinder end wall toward said fixed blade; a movable blade connected to said shaft and mounted to slide along said guide rails toward and away from said fixed blade; spring means surrounding the stem portion of the shaft that is inside said cylinder when the fixed and movable blades are separated and compressed between said cylinder end wall and piston head for biasing said piston head away from said cylinder end wall, said spring being capable of being compressed into the space between the cylInder end wall and the annular surface when the piston engages the annular abutment surface; a momentum dampening means for absorbing the energy of said movable blade and drive shaft after the movable blade has cut through the thickest part of the horn and the piston head makes contact with said annular abutment surface; and means for selectively supplying compressed gas from a remote source of gas under pressure to said gas cylinder to produce movement of said movable blade toward said fixed blade and cause severance of the animal''s horn, and for venting said gas cylinder to the atmosphere to thereby allow said movable blade to move away from said fixed blade following severance under the action of said spring means. 